Adjustment locking device for chair base



June 6, 1961 R. A. CRAMER, JR 2,987,110

ADJUSTMENT LOCKING DEVICE FOR CHAIR BASE Filed Feb. 8, 1960 2 Sheets-Sheet 1 gig. 1. r

INVEN TOR. Roy A. Cramen/n June 6, 1961 R. A. CRAMER, JR 2,987,110

ADJUSTMENT LOCKING DEVICE FOR CHAIR BASE Filed Feb. 8, 1960 2 Sheets-Sheet 2 Mum:

INVENTOR. Roy A. Crcrmer Jr.

United States Pat 2,987,110 ADJUSTMENT LOCKING DEVICE FOR CHAIR BASE Roy A. Cramer, Jr., Kansas City, Mo., assignor t Cramer Posture Chair Company, Inc., Kansas City, Kans., a corporation of Missouri Filed Feb. 8, 1960, Ser. No. 7,323 6 Claims. (Cl. 155-93) This invention relates to an adjusting locking device for chair bases, and more particularly to means for raising and lowering the seat of the chair relative to the base portion and locking the same in place so that the height of the chair seat will remain the same during use.

With locking devices heretofore devised it has been necessary to use levers, screws-and the like for adjusting the chair seat with respect to the base and for locking the same after it is adjusted to the desired height, thus necessitating use of tools and requiring time for adjustment. No simple arrangement has prior to applicants been devised to accomplish this purpose and to hold the chair pedestal or standard from turning with respect to the base after it is adjusted.

It is the principal object of the present invention to provide a collar for free slidable movement vertically of the pedestal, the collar having an inside circumference slightly larger than the outside diameter or circumference of the threaded pedestal and which has means for engaging the threaded pedestal to turn with the pedestal by rotating the seat frame when the chair seat is to be adjusted and having means to engage the base to prevent rotation of the pedestal after the seat has been adjusted as to height with respect to the base.

Other objects of the present invention are to provide a chair base having a threaded hub for receiving the threaded pedestal and having legs extending therefrom; to provide a chair seat having a depending sleeve having a socket forming a bearing engaging the upper end of the pedestal for rotation of the seat on the pedestal and having spaced notches in its lower edge; to provide the threaded pedestal with a longitudinal vertical groove in one side thereof; to provide a collar slidable upon the threaded pedestal and having a key in one side for engaging in the vertical slot in the pedestal so that the collar will rotate with the pedestal; to provide the hub with spaced notches intersecting the opening therethrough so that the key in the collar will engage therein to lock the pedestal to prevent rotation thereof when the seat is adjusted; to provide means in the pedestal cooperating with the key in the collar to hold the collar in an elevated position so that the collar may be elevated and held in place on the pedestal above the threaded portion and the key therein being in said slot; to provide the collar with a spring urged plunger for engaging in a notch in the sleeve, whereby rotation of the seat frame will rotate the pedestal to adjust the height of the seat with respect to the base and when the pedestal is adjusted the collar may be lowered so that t .e key will engage the notches in the base to prevent rotation thereof, and to provide a device of this character simple and economical to manufacture.

In acornplishing these and other objects of the invention, I have provided improved details of structure, the preferred forms of which are shown in the accompanying drawings wherein:

FIG. 1 is a fragmentary side view showing the collar on the pedestal disengaged from the hub.

FIG. 2 is a fragmentary cross-sectional view showing the collar in elevated position and locked in place by the locking means.

FIG. 3 is a vertical cross-sectional :view showing the collar in l wered pos tion oc edin th hub of he bas FIG. 4 is a cross-sectional view taken on a line 4-4, FIG. 1.

FIG. 5 is a cross-sectional view taken on a line 5.-5, FIG. 1.

1 designates a chair base having a hub 2 with a threaded opening 3 extending vertically therethrough for receiving a threaded pedestal 4. The base has the usual legs 5, 6, 7 and 8 secured to the hub and a seat frame 9 has a depending sleeve or boss member 10 extending downwardly from the seat frame which provides a socket 11 forming a bearing portion 12 for the upper end 13 of the threaded pedestal 4. The threads 14 on the pedestal terminate below the lower end 15 of the depending sleeve 10 and the pedestal 4 is provided with a vertical groove 16 for a purpose later described.

The pedestal 4 is provided near its upper end with an annular groove 17 and the depending sleeve 10 is provided with a transverse threaded bore 18 for retaining a set screw 19 having its inner end 20 engaging in the groove 17 which retains the seat frame on the pedestal and allows the same to freely rotate thereon.

The upper portion 21 of the hub 2 has suitable notches or sockets preferably circumferentially spaced and opening upwardly therein. The notches or sockets preferably intersect the bore 3 around the pedestal 4 and extend radially therefrom.

Encircling the threaded pedestal 4 is a collar 23 the inside diameter of which is slightly larger than the outside diameter of the threaded pedestal 4 so that it will freely slide vertically thereon. The collar may be of any desired shape but I have here shown it to be substantially cy lindrical having plane upper and lower sides 24 and 25 and the edge 26 is curved slightly inwardly forming an annular groove as indicated at 26 so that the same may be grasped with the hand and rotated as later shown.

Extending inwardly from the opening 27 of the collar in one side thereof is a notch 28 for receiving a key 29 which extends below the collar forming a lug 30 as illustrated in FIG. 2. The key 29 has a threaded opening 31 in the outer edge thereof which registers with an opening 32 in the collar 23 for receiving an Allen screw or the like 33 to hold the key in place in the collar. The key as illustrated in FIG. 2 engages in the vertical notch 16 so that the pedestal 4 cannot rotate without rotation of the collar 23.

As illustrated in FIG. 3 the lug 30 on the key 29 depending below the collar engages in one of the notches 22 in the top of the hub 2 when the collar is lowered to the hub and thus the pedestal will not rotate with respect to the hub due to the key being locked in the pedestal and also in the hub. The chair seat frame will freely rotate on the pedestal and will always remain the same height from the base when the pedestal is locked to the hub.

The pedestal 4 has a threaded horizontal bore 34 (FIG. 2) providing a transverse opening therein and said here tapers towards the'notch 16 as indicated as 35 to provide a stop for a ball 36 urged towards the tapered edge of the opening 34 by a spring 37, the spring having its other end engaging against a set screw 38 engaging in the threaded bore opening 34. The inner face 39 of the 'key 29 is provided with a recess 40 as best illustrated in FIG. 2 adapted to be engaged by a portion of the ball 36 ex tending beyond the opening 34 into the groove 16 to provide a lock in the pedestal for the collar as is now to be described. 7

When it is desired to change the height'of the chair seat with respect to the base, the collar 23 is raised by hand to disengage the lug 30 of the key 29 from the notches or socket-s 22 in the hub 2 and is raised vertically 9.1 th Pedesta .4 nti the pr ng urge l kin all 36 3 engages in the recess 40 to retain the collar against the lower end 15 of the sleeve as shown in FIG. 2.

One side of the collar 23 is provided with a vertical opening 41 counterbored as indicated at 42 for receiving a plunger 43 having a reduced shank portion 44 which extends through the opening 41 and is provided with a a keeper or stop portion thereon as indicated at 45 to retain said plunger assembled in the collar. A coil spring 46 surrounds the shank to retain the plunger 43 extended above the face 24 of the collar 23 when in normal position. When the collar is released from the hub 2 and raised vertically, the plunger 43 will engage against the lower end of the boss 10 of the frame 9 and upward pressure on the collar will cause the plunger to be pressed into the counterbore 42 as shown in dotted lines 47, FIG. 2. The lower end 15 of the boss 10 has suitable notches 48 circumferentially spaced and opening downwardly therein. The notches 48 preferably intersect the bore 11 around the pedestal 4 and extend radially therefrom. Slight rotation of the seat frame 9 with the boss 10 depending therefrom will align one of the notches 48 with the plunger 43 and the spring 46 will force said plunger into engagement with a notch 48 thus locking the seat frame to the pedestal as shown in FIG. 2.

When the collar is in the position shown in FIG. 2 and, due to engagement of the key 29 in the vertical groove 16 in the pedestal and the plunger engaged in a notch 48, rotation of the seat frame 9 will rotate the pedestal 4 and thus raise or lower the pedestal as desired in the hub 2 due to the threaded engagement therewith to raise or lower the seat frame. When the desired distance between the seat and chair base is accomplished by rotation of the seat frame and pedestal, the plunger is disengaged from the notch 48 in the sleeve 10 by lowering the collar by hand by merely pressing downwardly thereon until the lug on the key will engage the top 21 of the hub and continued rotation of the collar 23 will cause the lug 30 on the key 29 to drop into one or the other of the notches 22 in the top of the hub thereby locking the pedestal against rotation (FIG. 3). The seat frame is freely rotatable on the pedestal and since the pedestal is locked against rotation, the seat will always remain in the same spaced relation from the base during use of the chair.

It will be obvious from the foregoing that I have provided an improved locking device for a chair base and pedestal whereby there is positive locking of the pedestal against rotation during use of the chair while the chair seat is freely rotatable on the pedestal.

What I claim and desire to secure by Letters Patent is:

1. In a chair, the combination of a base having a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches around the threaded opening therein, a seat frame normally freely rotatable on said pedestal, said pedestal having a groove extending vertically along one side thereof and extending slightly above said threads on the pedestal, a cylindrical locking collar slidable on said threaded pedestal and rotatable therewith, a key in said collar and engaging in the vertical groove of the pedestal having one end extending below the collar for engaging in a notch in the top of the hub, means on said pedestal for holding the collar in elevated position on said pedestal, and means on said collar engaging means on said seat frame, whereby rotation of the seat frame will rotate the pedestal to adjust the seat frame with respect to the base and lowering said collar to said hub will cause the same to lock the pedestal against rotation during use of the chair.

2. In a chair, the combination of a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches around the threaded opening therein, the upper end ofthe pedestal being rounded, a seat frame, a sleeve member on said seat frame and depending therefrom forming a socket with its upper end rounded to form a bearing for the pedestal to allow the seat frame to freely rotate thereon, said pedestal having a groove extending vertically along one side thereof, a cylindrical locking collar slidable on said threaded pedestal, means in said collar engaging in the vertical groove of the pedestal and for engaging in a notch in the top of the hub, means on said pedestal for holding the collar in elevated position on said pedestal, and means on said collar engaging means on said sleeve whereby rotation of the seat frame will rotate the pedestal to adjust the seat frame with respect to the hub and lowering said collar to said hub will cause the same tpl lock the pedestal against rotation during use of the 0 air.

3. In a chair, the combination of a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches intersecting the threaded opening therein, the upper end of the pedestal being rounded and the threads on said pedestal terminating short of said upper end, a seat frame, a sleeve member on said seat frame and depending therefrom forming a socket with its upper end rounded to form a bearing for the pedestal to allow the seat frame to freely rotate thereon, means retaining the seat frame on the pedestal, said pedestal having a groove extending vertically along one side thereof and extending slightly above said threads on the pedestal, locking collar slidable on said threaded pedestal, means in said collar and engaging in the vertical groove of the pedestal having one end extending below the collar for engaging in a notch in the top of the hub, means on said pedestal for holding the collar in elevated position on said pedestal, the lower edge of said sleeve having spaced notches therein, and means carried by said collar for engaging in one of said notches on said sleeve when the collar is elevated whereby rotation of the seat frame will rotate the pedestal to adjust the seat frame with respect to the hub and lowering said collar to said hub \w'll cause the same to lock the pedestal against rotation during use of the chair.

4. In a chair, the combination of a base having a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches intersecting the threaded opening therein, the upper end of the pedestal being rounded and the threads on said pedestal terminating short of said upper end, a seat frame, a sleeve member on said seat frame and depending therefrom forming a socket with its upper end rounded to form a bearing for the pedestal to allow the seat frame to freely rotate thereon, said pedestal having a groove extending vertically along one side thereof and extending slightly above said threads on the pedestal, a collar slidable on said threaded pedestal and rotatable therewith, the inside of said collar having a vertical groove therein, a key in the groove in said collar and engaging in the vertical groove of the pedestal having one end ex tending below the collar for engaging in a notch in the top of the hub when the collar rests on said hub, means on said pedestal for holding the collar in elevated position on said pedestal, the lower edge of said sleeve having at least one notch therein and means on said collar engaging in said last named notch, whereby rotation of the seat frame will rotate the pedestal to adjust the seat frame with respect to the base and lowering said collar will cause the lower end of the key to engage in a notch in said hub to lock the pedestal against rotation during use of the chair.

5. In a chair, the combination of a base having a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches intersecting the threaded opening therein, the upper end of the pedestal being rounded and the threads on said pedestal terminating short of said upper end, a seat frame, a sleeve member on said seat frame and depending therefrom forming a socket with its upper end rounded to form a bearing for the pedestal to allow the seat frame to freely rotate thereon, means on said sleeve cooperating with said pedestal to retain said seat frame on said pedestal, said pedestal having a groove extending vertically along one side thereof and extending slightly above said threads on the pedestal, a collar slidable on said threaded pedestal and rotatable therewith, the inside of said collar having a vertical groove therein, a key in said collar and engaging in the vertical grove of the pedestal having one end extending below the collar for engaging in a notch in the top of the hub when the collar rests thereon while the chair is in use, spring and ball means on said pedestal for holding the collar in elevated position on said pedestal, at least one notch in the lower edge of said sleeve, and means on the upper edge of said collar engaging in said notch in said sleeve whereby rotation of the seat frame when the collar is elevated against said sleeve will rotate the pedestal to adjust the seat frame with respect to the base and lowering said collar to said hub will cause the key to engage in a notch in the hub to lock the pedestal against rotation during use of the chair.

6. In a chair, the combination of a hub with a vertical threaded opening therein, a threaded pedestal engaging in said threaded opening in the hub, the upper edge of said hub having spaced notches surrounding the threaded opening therein, the upper end of the pedestal being rounded, a seat frame, a sleeve member on said seat frame and depending therefrom forming a socket with its upper end rounded to form a bearing for the pedestal to allow the seat frame to freely rotate thereon, said lower edge of said sleeve having at least one notch therein, said pedestal having a groove extending vertically along one side thereof, a cylindrical locking collar slidable on said threaded pedestal, means in said collar engaging in the vertical groove of the pedestal and for engaging in a notch in the top of the hub, means on said pedestal for holding the collar in elevated position on said pedestal against said sleeve, said collar having an openingextending vertically through one side thereof, a spring urged plunger in said opening and extending above the upper side of the collar for engaging in said notch in said sleeve when the collar is elevated, whereby rotation of the seat frame will rotate the pedestal to adjust the seat frame with respect to the hub and lowering said collar to said hub will cause the same to lock the pedestal against rotation during use of the chair.

References Cited in the file of this patent UNITED STATES PATENTS 1,399,465 Collier Dec. 6, 1921 1,513,695 Dawson Oct. 28, 1924 1,589,847 Hansen June 22, 1926 2,058,451 Herold Oct. 27, 1936 2,412,451 Foote Dec. 10, 1946 2,026,298 Bouman Dec. 31, 1955 FOREIGN PATENTS 581,856 Great Britain Oct. 28, 1946 

